Hard drive platters: they’re pretty important, and there’s a good chance that you’re using them at this exact moment. But what are they?
Well, if you’ve ever looked into hard drives—literally or figuratively—you know that inside every hard drive are spinning platters, which store all of your files. They’re magnetic, which allows the hard drive’s read/write heads to identify binary units of information. We’ll get into that a bit more in a second.
But first, here’s a simple question: What are hard drive platters made of? Are they all made of the same stuff?
Well, kind of. Sort of. Not really. Here’s what you need to know.
Different Types of Hard Drive Platter Materials
Hard drive platters are typically made from aluminum (desktop computers) or glass (laptop computers). They also have a ceramic substrate, which prevents cracking due to changes in temperature.
Different materials have different advantages; aluminum is inexpensive and light, while glass allows for easier manufacture of high-density disks. This is becoming more important, as consumers generally expect new disk drives to hold a terabyte of data or more.
These materials are then coated with a thin magnetic material, as well as a protective carbon coat and a lubricant layer that helps to prevent the read/write heads from contacting the platters (although the high spin speed plays a bigger role by creating a cushion of air).
After the hard drive platters are manufactured, they’re buffed to ensure a completely even surface, which is vital for ensuring hard drive operation. A bit of dust can throw off hard drive operation in some cases, so the details matter.
Is There Any Advantage to Certain Hard Drive Materials?
Yes, but major manufacturers (Western Digital, Toshiba, Seagate, and others) tend to follow the same processes when manufacturing hard drive platters. Major manufacturers are moving towards glass, since hard drives are shrinking and glass offers several major advantages over aluminum in small spaces.
New types of glass are extremely flat, so the heads can get closer to the hard drive platters. Manufacturers can also eliminate some of the steps that they use to smoothen aluminum drives, saving money in the production process.
Aluminum is still less expensive overall, but the cost of glass platters has come down considerably.
So, can you determine if a hard drive is constructed properly by figuring out the platter material? Not really; bigger factors include the drive’s firmware, electronics, and general construction. You can’t really determine if a hard drive is a well-built unit just by looking at how the platters are made, unless you really, really know what you’re looking for.
For the average consumer, hard drive platter material isn’t particularly important—but it’s certainly interesting.